Department of Physics & Astronomy

Xperimenting Xploring Xperiencing down to the Femtoscale

August 26, 2022l Hit 577
Date : November 30, 2022 16:00 ~
Speaker : Navin Alahari (GANIL(프랑스 국립대형가속기 연구소))
Professor : Prof. Dohun Kim, Prof. Sunghoon Jung
Location : 56동105호 +온라인 중계 (코로나 방역 상황에 따라 변동 가능)
The existence of the atomic nucleus as we know it, was demonstrated around 100 years ago by scattering of alpha particles from a radioactive source on a gold foil - the Rutherford experiment - and subsequently studied using accelerated beams of stable elements. Today it has become possible to create and accelerate beams of short lived (~msec) designer nuclei in the laboratory and to study their properties. These exotic nuclei are produced from stable nuclei by altering the neutron/proton ratio, exhibit new phenomena like halos, skins, new ‘magic numbers’, exotic radioactivities, etc., different from those seen near the valley of beta stability. Facilities differing in methodologies and capacities for exploring these exotic nuclei have been setup worldwide to study their unusual properties and their influence on nuclear reaction mechanism. The RAON facility being built in South Korea will be addressing many related interesting questions. In this talk, after a brief historical review, we explore some aspects at the femtometer scale using the available microscopes at GANIL to address some aspects of these key questions The various studies that we will discuss use ion high intensity (~1012 particles/s) stable ion beams (12C to 238U) up to 95 MeV/nucleon and exotic beams of nuclei (which live for a very short time with lifetimes ranging from ~ µsecs to msecs). The intensities of these exotic beams range from a few particles/s to ~107 p/s. More recently, a new very high intensity superconducting LINAC has also been commissioned that will also provide intense neutron beams. These numerous types of beams are coupled to versatile detection facilities (active targets, powerful spectrometers, 4p charged particle detectors, g-ray tracking detectors, etc.) built by various international collaborations. These tools help us explore the behavior of nuclei under various conditions of excitation energy (heating to different temperatures), angular momentum (spinning), and isospin (different composition in terms of neutrons and protons).